- this->attr_get<T>(keyval, &value, &flag);
- if(flag!=0){
- int ret = call_deleter<T>((T*)this, elem, keyval,value,&flag);
+ auto p = attributes()->insert({keyval, attr_value});
+ if (!p.second) {
+ int ret = call_deleter<T>((T*)this, elem, keyval,p.first->second,&flag);
+ // overwrite previous value
+ p.first->second = attr_value;